Using the I-Rotary Apex Seal - FAQ

Lubrication and Pre-Mix

The I-Rotary Apex Seal (I-RAS) can be treated just like the Mazda OEM apex seal in all applications.

We strongly recommend the additional use of a high quality 2-stroke oil in the fuel to improve the longevity of the apex seal (Mazda’s or I-Rotary or any other aftermarket apex seal).

Importantly, pre-mixing oil in the fuel also helps lubricate the rest of the sealing grid components and wear surfaces. We even use the below recommendations for our ceramic seals, which do not wear, due to the friction benefits on the entire sealing grid resulting in more power and longer life.

Premix of Premium “2-Stroke” Oil in Fuel

High Performance, Track-day or Racing Engines

Fuel Type

Milliliters per Liter of Fuel

US Fluid Ounces per US Gallon


(Pure Alcohol)

15-20 ml/Liter

2.0-2.5 oz/gallon

E85 Fuel

15 ml/Liter

2.0 oz/gallon


12-15 ml/Liter

1.5-2.0 oz/gallon

Non-Racing Engines with Functioning Oil Metering Pump (OMP)

Fuel Type

Milliliters per Liter of Fuel

US Fluid Ounces per US Gallon


10 ml/Liter

1.25+ oz/gallon

E85 Fuel

15 ml/Liter

2.0 oz/gallon


Apex Seal to Rotor Groove Clearance

It is important that whatever value is selected from the recommended range below that all apex seals have the same clearance.







0.0762 mm

0.127 mm

0.003 in.

0.005 in.


Engine “Break-in” Procedure

Maximum Performance will be achieved with a proper engine “Break In” procedure.

Every engine builder has their own break-in program; however, many engine builders suggest that the initial 800-1000 miles should be driven as easy as possible with minor acceleration events towards the later stages of this mileage to allow the bearings, seals, and other wear surfaces to mate to each other.

The break-in procedure with the I-Rotary apex seal is similar to when using the Mazda factory apex seal, however, the I-Rotary Apex Seal may require greater break-in time than other apex seals due to their low wear rate.

Due to the low wear rate we recommend that the engine break-in periods be extended when using our seals.

At a minimum, run engine for a few hours after initial start at low RPM and light loads.

Note about Engine “Break-in” Procedure on the Dyno

Due to the increased break-in time mentioned above, when the engine/car is being tuned on the dyno, we recommend increasing the number of steps in RPM and Throttle on the way up to the maximum power tune. This gives the seal a greater opportunity to bed-in under power and will provide a better tuning experience.


Rotor Housings

The best performance results for the I-Rotary Apex Seal are obtained with new rotor housings.

Used rotor housings can be used but must be inspected to make sure that they are:

  1. Within the width dimensions recommended by Mazda
  2. Not heavily shrunk or distorted along the leading spark plug area
  3. Not distorted along the exhaust port
  4. Have a good chrome surface that is smooth, with low wear, free of scratches and without any chipping along the edges.

Use of a used rotor housing that is not as described above will damage any metallic apex seal, lowering its life.



The best performance results for the I-Rotary Apex Seal are obtained with new rotors.

Used rotors can be used but must be inspected to make sure that they do not have damaged or mis-cut apex seal grooves and that the proper apex seal groove clearance can be obtained.

Use of a used rotor with damaged or mis-cut apex seal grooves will damage any metallic apex seal.


Fuel Deceleration Cutoff

It is extremely important that during deceleration the pre-mixed fuel continues to flow into the engine for any apex seal. This is most important if the engine is not using the Oil Metering Pump (OMP).

This allows the entire sealing grid to remain lubricated during deceleration events such as coasting the engine from a 7000 RPM with the foot off the throttle.

Mazda stock ECU usually cuts the fuel in deceleration to improve gas mileage.  You will need to disable this feature to allow the fuel to continue to flow during deceleration on the Mazda’s ECU or in any other aftermarket ECU.


    What Springs to Use

    I-Rotary Apex Seal Model

    Spring Part Number (P/N)

    13B - 2mm - 2pc.

    (Mazda P/N: 0000-01-9113-ST)

    Mazda P/N N3H3-11-C06 (Outer Spring)

    Mazda P/N N3H3-11-C04 (Inner Spring)

    Renesis - 2mm - 2pc.

    (Mazda P/N: 0000-01-9116-ST)

    Mazda P/N N3H3-11-C06 (Outer Spring)

    Mazda P/N N3H3-11-C04 (Inner Spring)

    13B - 3mm - 2pc.

    Mazda P/N:  1757-11-304

    12A - 3mm - 2pc.

    Mazda P/N:   1011-11-304B


    Buy from Our Distributors Here


    These I-Rotary Apex Seals are competition components and are sold "As Is" and without warranty of any kind.  All implied warranties including all warranties of merchantability or fitness for a particular purpose are hereby disclaimed. Purchaser acknowledges that they shall be responsible for and bear any and all costs associated with the use of these I-Rotary Apex Seals. Purchaser acknowledges that installation of these I-Rotary Apex Seals may cause the vehicle to be unable to be lawfully used on public highways and assumes all risks and expenses thereof.

    Extremely Important: Do not use these parts in any type of Aircraft or Flying Vehicle